Caption: Coral (Dendrophthya sp.). This soft coral is found in warm waters. Unlike most corals it can live in caves, or under ledges, as well as in lighter conditions. It feeds on phytoplankton (microscopic plants), by sucking water into its body and filtering out the organic matter. It expands in size dramatically when feeding, as its branches swell. Photographed in the Red Sea, Marsa Alam, Egypt.